Mountings for picture tube grids



Jan. 28, 1958 K, MI HENRY E 2,821,644 I MOUNTINGS FOR PICTURE TUBE GRIDS 4 Sheet-Sheet 1 Filed Nov. 10, 1954 INVENTORS KENETH M.HENRY HARVARDB.V|NCENT ATTORNEYS 1958 K. M. HENRY ET AL 2,821,644

MOUNTINGS FOR PICTURE TUBE cams 4 Sheets- Sheet 2 Filed Nov. 10, 1954Ill I i 3 m I INVENTORS I KENETH M. HENRY BY HARVARD BfiVlNC ZEN'T mw7ATTORNEYS Jan. 28, 1958 K. M. HENRY ETAL MOUNTINGS FOR PICTURE TUBEGRIDS 4 Sheets-Sheet 4 Filed Nov. 10, 1954 INVENTORS KENETH M. HEN RY BY7 HARVARD B.V|NCENT ww ATTORNEYS United States Patent C) MOUNTINGS FORPICTURE TUBE GRIDS Kenneth M. Henry and Harvard B. Vincent, Toledo,Ohio, assignors to Owens-Illinois Glass Company, a corporation of OhioApplication November 10, 1954, Serial No. 467,960

11 Claims. (Cl. 313-78) Our invention relates to picture tubes. Itprovides new and improved means for mounting grids in cathode ray tubesand in certain forms thereof is particularly adapted for use in colortelevision.

In picture tubes for color television as they are commonly constructedat the present day, the grid structure which controls the color registryis supported on a frame of substantial width which must be containedwithin the envelope, thereby making the area in which the picture may beproduced substantially smaller than the face of the tube. If the widthof the frame is decreased its stiffness becomes inadequate for end use.

An object of the present invention is to provide an improvedconstruction by which the area available for the picture is increased tosubstantially the full area of the face plate of the picture tube.

The invention provides a construction in which. relatively thin metalframe members or strips of sheet material are extended along the innermarginal surfaces of the face plate and bonded thereto. Such stripsprovide a frame or support for the fine wires forming the grid. Owing tothe method of attachment of the strips to the envelope of the tube, theyare of adequate stifiness to serve the requirements of end use and atthe same time provide for a comparatively large picture area. thepurpose of attaching the grid wires to the supporting strips the lattermay have an edge portion offset or bent to U-form and slotted to formrows of lugs or hooks for holding the grid wires or strands, the lugsand spacing slots being of a width corresponding to the required spacingof the grid wires.

In one form of our invention the grid supporting strips overlie and areadhered to the inner wall surfaces of the marginal flange of the faceplate. strips may be attached to the enclosing envelope by means ofeither solid or tubular studs sealed in the walls of the picture tube,the grid frame or strips being anchored to the studs.

For

In other forms the The grids as mounted in the tubes or envelopes areFig. 3 is a fragmentary perspective view showrng a grid supporting stripmounted on the face plate of the tube;

Fig. 4 is a view similar to Fig. 2, showing .a modified form of gridsupporting strip;

Fig. 5 is a fragmentary diagrammatic plan view ofthe grid and supportingstrips;

ing strips as seen in side elevation;

Fig. 7 is a fragmentary perspective view of the grid supporting stripsshown in Figs. 46;

Fig. 8 is a view similar to Fig. 4 showing a further modification of themeans for mounting the grid;

Figs. 9, 10, and 11 are fragmentary views illustrating various alternatemeans for attaching the grid supporting strips to the face plate;

. Fig. 12 is afragmentary view Showing a further modification comprisinga solid stud by which the grid frameis anchored to the face plate;

Fig. 13 is a fragmentary perspective view of a metal form or strip forcarrying the grid;

Figs. 14 and 15 are fragmentary views similar to Fig. 12 showing furthermodifications of the grid mounting means; and

Fig. 16 is a view of a plural strip supporting frame for the grids.

Referring to Figs. 1, 2 and 3, which illustrate one form of ourinvention, the picture tube comprises a funnel-shaped body 20, stem 21and a face plate 22 made of glass and sealed to the body along the line23. The face plate may be of conventional, substantially rectangular,elongated form as viewed in plan. The face plate is convex and formedwith a marginal flange 24 to which Each strip 26 has its upper marginalportion bent or curved inwardly in the form of an inverted U. Slots 28divide this margin into a multiplicity of narrowly spaced lugs or hooks29 which anchor the screen wires and hold them in narrowly spacedparallel relation.

The means for securing the strips 26 to the face plate includes a sheetor layer 31 of felt or the like cemented to the rear surface of thestrip 26. A sheet or layer 32 of suitable bonding material between thefelt 31 and the face plate provides a means for securing the strip 26 tothe face plate. The layer 32 may consist of a frit.

A further specific method of bonding the thin metal strips to the wallsurface of the face plate consists in coating one or both of theseparts, over suitable areas, with a brazing glass which melts and adheresat a temperature below the temperature at which distortion of the faceplate becomes a serious problem. This brazing glass should be one whichwill not soften and permit the metal to pull away'from the glass at atemperature of 750 F., to which temperature the assembly may be heatedby the tube manufacturer during his processing.

Brazing glass as herein referred to includes any compound of metallicoxides suitable for this purpose. Following the application of thebrazing glass the face plate and the thin metal strips are assembled ina fixture which serves to locate and seat the metal strips as theassembly is heated in an oven to a temperature at which the brazingglass melts and adheres.

As a further modification of the strip attaching means,"

the inner face of the side wall or flange 24 may be metallized by theuse of a silvery compound such as may be obtained on the open market.This area may then be electroplated and the grid supporting strip 26attached thereto by soldering. A solder having a high softening point.should be used to withstand the high temperature to which the tube issubjected during manufacturing or assembling operations. Such softeningpoint should prefr'erably be above 750 F.- f I Patent ed Jan. 28, 1958Figs. 4-7 illustrate a modified construction for mounting two insulatedgrids in the face plate. These are adapted for use in tubes employingchromatic color design. In this construction upper and lower mountingstrips 35 and 36 are attached to the inner face of the flange 24. Thesestrips are separated by a baresurface strip 37 of the glass face platewhich forms an insulating area. The grid frames 35 and 36' may beattached to the face plate in the same manner as above described inconnection with Fig. 3, including the layers 31 and 32. The lower gridframe or strip 36 may be substantially similar to the structure shown inFig. 3, the upper portion of the strip being bent to U-forrn andcomprising downwardly extending lugs or hooks 37 spaced apart by slots38. The upper grid plate 35 has its lower portion offset inwardly and isslotted to provide downwardly'extending lugs or hooks 39 spaced apart byslots 40. As shown diagrammatically in Fig. 5, the upper lugs 39 may beoffset laterally with respect to the lower lugs 37 so that the wires 42forming one of the grids alternate with the wire 43 (shown in brokenlines) forming the other grid, the alternate wires being equally spacedapart. The lower ends of the upper lugs 39 are formed with upwardlycurved surfaces 44 which may assist in holding the wires 43 in theuniformly spaced position between the wires 42. The two grids or sets ofwires 42, 43 are held in the same plane or at a common level by theinterwoven wires or strands 46 of glass or other insulating material.

The grid wires are narrowly spaced. For example, they may have a spacingof .030". The screen plate behind them (not shown) is provided, forvexample, with stripes of phosphor .015" wide fluorescing in the colors.in the usual sequence, red, green, blue, green, red.

Figs. 9, 10 and 11 illustrate various alternate structures for attachingthe grid supporting strips to the face plate. Referring particularly toFig. 9, a cylindricalmetal tube 50 is mounted in the flange portion 24of the face plate, a bolt 51 extends through a restricted opening in theinner end of the cylinder 50, the head 52 of the bolt being within thecylinder and bearing against the end wall of the cylinder. The bolt hasa screw-threaded connection with the strip 26. Thismay comprise a nut 53welded to the strip and in which the bolt is threaded. The cylinder 50is mounted within a cylindrical opening 54 extending through the wall ofthe face plate. The cylinder is preferably attached by fusion to thewall surface of the opening 54. The screw head is provided with a kerf56 to receive a tool extended through the open cylinder for attachingand adjusting the bolt to the nut 53. Following the installation of thegrid the outer end .of the cylinder is closed by a disk 57 which issoldered in place. Theisolder should have a softening point, preferablyhigher than 750 F. which is the usual baking temperature at which theassembly will be heated by the tube maker during processing. A,pluralityof these tube assemblies arerused for the attachment of .each of thestrips 26. These attachments may be located at intervals lengthwise ofthe strip as indicated diagrammatically on Fig. 8, at the intersectingpoints of the broken line 58 extending 'lengthwiseof the strip and thecross lines 59.-

Fig. 10 illustrates a modification of-the structure shown in Fig. 9,adapted for use with two grids .such; as heretofore described inconnectionwith Figs. 4-7. Intthisistructure the nut 53 is attached tothe frontfaceofatheastrip 26. A second strip 26* is mounted behind thestrip. 26 for attachment of the wiresforming'the secondgrid. The strip26 may be made-of. insulating material.

In Fig. 11 a grid supportingstrip 26! is weldedor brazed tothe frontface of thenut -3 andinsulatedfromthe:strip 26. 'In each of thestructures shown inEigs. 9., and '11, the boltserves asa tension :andtakeupmeans between the tubes and strips 26 :for applying tension to thegrid wires.

Figs. 12-16 illustrate further modified constructions 4 in which solid,cylindrical metal studs 60 are employed for attaching the grid frames orstrips to the face plate. The studs 60 consist of a metal matching theglass for expansion characteristics, the studs being soldered by fusionat suitable intervals along the two opposite sides of the face plate 26.As shown in Fig. 12 the opening in which the stud is mounted extendsonly part way through the glass wall. Each stud is formed adjacent toits exposed end with a groove 61. The strip 26 is formed with slots 62to receive the studs 60, with the side walls of the slots in the grooves61. The, slots'are spaced to correspond with the spacing of the studs.Slotted spring washers 63 are mounted, on the strips 26 and serve tohold the strips in position on the studs.

Fig. 14 illustrates a mounting for plural grids. Such mounting includesthe strips 26 and 26 In this construction the slots are formed in thestrip 26 for attaching the assembled strips to the studs60. The strips26 and 26 may be spacedapart and insulated from each other by aninterposedstr'ip 64" of insulating material. As shown in Fig. 14 theface plate is formed with openings 54 extending entirely through theglass wall.

Figs. 15 andl6illustrate a mounting for plural grids in which the strips26 and.2 6 are both formed with slots permittingthem to be mounted onthe studs 60. In this structure the strip 26 is positioned behind thestrip 26, that is, interposed'between the strip 26'and the glass wall. Asleeve 65 'of insulating material is mounted on the stud 60. Insulatingstrips or washers 66 may be interposed'between the strips 26' and 26 Thespring washers 63 in this form of mounting are positioned in front ofthe grid supportingstr'ips. The lugs .37'and 39 on the strips 26 and 26may be arranged in staggered relation as above described in connectionwith Figs. 5-7.

Modifications may be resorted to within the spirit and scope of ourinvention.

We claim:

1. A picture tube comprising an envelope, a grid therein and means forattaching the grid to the walls of the envelope, the attaching meanscomprising strips of thin sheet material extending along the said wallswith a major portion of each strip lying flat against the side walls,and means for anchoring'said strips to said walls, the grid comprising amultiplicity of narrowly spaced fine strands anchored to said strips,the said major portions of said strips being substantially perpendicularto the grid strands.

2. The picture tube definedin claim 1, the said attaching strips eachhaving a marginal portion thereof offset and slotted to form amultiplicity of spaced lugs in a row extending lengthwise of the stripand by which the gridstrands are held.

3. The picture tube defined in claim 2, the said marginal portions ofthe strips being bent to substantially U-form, the said lugs and slotsbeing of approximately equal width and holding the said grid strandsnarrowly and equally spaced.

4; The picture tube defined in claim 1, the envelope consisting ofglass,the said strips consisting of'sheet metal, and a layer of bondingmaterial interposed between the said strips andthe wall surfaces of theenvelope and forming a bondhetween said strips and envelope.

5. Theapparatus defined in claim 4, said bonding material comprising afrit.

6. The combination set forth in claim 1, the said strips consisting 'ofmetal welded to theinner wall surfaces ofthe envelope.

7. A picture tube comprising a body and a face plate formed with aperipheral flange, a grid mounted within the tube, means for attachingthe grid to the face plate comprising sheet metal strips extendinglengthwise along opposite wall surfaces of said flange, means foranchoring said strips tosaid flange, each said strip having a marginalportion extending lengthwise thereof and offset inwardly from the body'of the strip, the saidbody of the strip lying flat against the flangethroughout its area, said offset portion being slotted to form amultiplicity of lugs with interposed spaces substantially equal in widthto the lugs, the grid comprising a multiplicity of fine wires anchoredto said lugs.

8. A picture tube comprising an envelope, grids mounted therein, eachgrid comprising a multiplicity of parallel strands, means for attachingthe grids to the walls of the picture tube, said attaching meanscomprising pairs of parallel strips of sheet metal extending along andparallel with inner wall surfaces of the envelope, the strands formingone of said grids being attached to one pair of said strips, the strandsforming the other grid being attached to another pair of said strips,each of the strips being formed with a multiplicity of narrow, narrowlyspaced lugs to which the grid strands are anchored and by which thestrands are held uniformly and narrowly spaced apart, and means forholding the strands of the two grids in the same plane, said plane beingperpendicular to the body portions of said strips.

9. The apparatus defined in claim 8, the said lugs on one pair of saidstrips being in staggered relation to the lugs on the other pair ofstrips, the strands of one grid alternating with those of the other.

10. The apparatus defined in claim 8, the said attaching strips being inparallel relation to the adjoining surfaces of the envelope and a layerof bonding material between each strip and the envelope by which saidstrips are bonded and rigidly adhered to the wall of the envelope.

11. The apparatus defined in claim 8, the said walls of the envelopeconsisting of glass, the said strips consisting of metal, the strips towhich the strands of one grid are attached lying substantially in thesame plane as the corresponding strips to which the strands of the othergrid are attached, the said strips being spaced apart with an interposedbare strip surface of the glass envelope insulating the strips of onegrid from those of the other.

References Cited in the file of this patent UNITED STATES PATENTS Re.23,735 Olson Nov. 10, 1953 2,540,835 Anderson Feb. 6, 1951 2,546,828Levy Mar. 27, 1951 2,682,620 Sanford June 29, 1954 2,695,372 LawrenceNov. 23, 1954 2,711,493 Lawrence June 21, 1955

